help find the distance travelled

Question

Bronwyn walks one lap of an oval at 2.5km/h and then jogs another eight laps of the oval at 5km/h. If it takes her 30 minutes total, how long in metres is each lap?

Answer 1

 

Hi Cassidy,

 

As the travelling time is given by

 

the travelled distance divided by the travelling speed,

 

if we let x denote the one lap distance in km,

 

the problem can be formulated as follows.

 

     x/2.5 + 8x/5 = 0.5     (30 minutes is an half hour.)

 

Multiplying both sides with 5,

 

     2x + 8x = 2.5

 

     10x = 2.5

 

     x = 0.25 [km]

 

0.25 km = 250 m.

 

So, each lap is 250 meters long.